1. Field of the Invention
The present invention generally relates to an electronically controlled cooling system and, more particularly, to a cooling system which includes a valve that is controlled by a microprocessor as a function of one or more temperature measurements made in conjunction with the cooling system of an internal combustion engine.
2. Description of the Prior Art
Many different types of systems are known to those skilled in the art for controlling the temperature of an internal combustion engine.
U.S. Pat. No. 6,331,127, which issued to Suzuki on Dec. 18, 2001, describes a marine engine. An engine for a watercraft includes a cooling system having a coolant supply. The coolant supply supplies an engine coolant jacket with a flow of coolant that is controlled by a temperature dependent flow control valve. The coolant supply also supplies an exhaust conduit coolant jacket independently of the engine coolant jacket.
U.S. Pat. No. 5,642,691, which issued to Schroeder on Jul. 1, 1997, discloses a thermostat assembly for a marine engine with a bypass. The thermostat assembly is used with a marine engine having a closed loop cooling system and provides an additional bypass for engine coolant flow. The assembly includes a housing having an inlet that receives engine coolant, a thermostat outlet that is connected to a heat exchanger, and a bypass outlet that is connected directly to a circulating pump that circulates engine coolant to the engine and bypasses the heat exchanger. A thermostat having a restricting plate is mounted in the thermostat outlet in the housing. The housing includes an internal structural standoff around the bypass outlet. When engine coolant enters the thermostat housing and the thermostat is closed, engine coolant passes between the thermostat restricting plate and the bypass standoff and flows through the bypass outlet directly to the circulating pump.
U.S. Pat. No. 5,555,855, which issued to Takahashi on Sep. 17, 1996, describes a water circulation system for a marine engine. The system improves the consistency of engine combustion by stabilizing the temperature of water flowing through the engine water jacket and by heating the intake manifold to a temperature within a desired temperature range. The desired temperature range is defined so as to optimize fuel vaporization without significantly affecting the volumetric efficiency of the engine. The water circulation system includes a control valve which directs water flow through the circulation system according to the water temperature exiting the engine water jacket. The valve recirculates water between the engine water jacket and a recirculation path until the water temperature reaches a predetermined lower temperature limit. The control valve then allows a portion of the water to flow through a heating jacket around the intake manifold to heat the intake manifold. If the temperature of the recirculating water reaches a predetermined upper temperature limit, the control valve directs all of the water through the heating jacket until the temperature of the water exiting the engine water jacket falls below the upper temperature limit.
U.S. Pat. No. 4,669,988, which issued to Breckenfeld et al on Jun. 2, 1987, describes a marine engine cooling system valve assembly. A marine propulsion device comprising an internal combustion engine including a coolant conduit having an upstream conduit portion, a downstream conduit portion, and a passage portion extending between the upstream portion and the downstream portion is described. The engine also includes a mechanism for controlling the flow of coolant through the coolant conduit, the controlling mechanism including a valve assembly located in the passage portion and including therein an opening, a temperature responsive mechanism located in the valve assembly and movable relative to the opening for opening and closing the opening in response to temperature variations.
U.S. Pat. No. 3,918,418, which issued to Horn on Nov. 11, 1975, discloses a marine engine cooling system employing a thermostatic valve, means and a pressure relief valve means. A pressure relief valve for the engine of an outboard motor includes a valve plate connected to a stem and spring loaded water cooling passageway, in close spaced relation to a then thermostatically controlled valve passageway. The stem extends outwardly through a water discharge chamber directly in communication with the discharge passageway to the lower unit of the motor.
U.S. Pat. No. 5,664,526, which issued to Logan et al on Sep. 9, 1997, discloses an apparatus for separating solid material from cooling water in a marine engine block. An apparatus for separating solid material from cooling water in the cooling system of the engine block of a marine engine is described. The engine block comprises a plurality of cylinder bores surrounded by a cooling passage through which cooling water is pumped. The bottom portion of the block includes a drain outlet that communicates with the cooling passage and a tubular separating member has a first generally horizontal section that is sealed within the drain outlet. The tubular separator also includes a second section that is located within the cooling passage and extends downwardly from the inner end of the first section and is located between two adjacent cylinder bores.
U.S. Pat. No. 5,579,727, which issued to Logan et al on Dec. 3, 1996, discloses a separating apparatus for the cooling system of a marine engine. An apparatus for separating solid material from cooling water in the cooling system of a marine engine is disclosed. The apparatus includes a hollow member or housing having an inlet to receive cooling water and having an outlet. A drain opening is located in the housing above the bottom surface of the housing and is connected through a suitable conduit to a temperature responsive drain valve. A generally J-shaped tubular member is disposed in the housing and has one end connected to the drain outlet while a second end is slightly above the bottom surface of the housing, out of alignment with the inlet.
U.S. Pat. No. 5,980,342, which issued to Logan et al on Nov. 9, 1999, discloses a flushing system for a marine propulsion engine. The flushing system provides a pair of check valves that are used in combination with each other. One of the check valves is attached to a hose located between the circulating pump and the thermostat housing of the engine. The other check valve is attached to a hose through which fresh water is provided. Both check valves prevent flow of water through them unless they are associated together in locking attachment.
Internal combustion engines typically use conventional mechanical thermostats to regulate the flow through cooling passages of the engine. The conventional mechanical thermostat typically blocks the flow through certain cooling passages when the cooling water is below a desired temperature. This allows the water to increase in temperature through prolonged exposure to heat producing portions of the engine. When a desired temperature is reached, the conventional mechanical thermostat opens its valve to allow the water to flow through the cooling passage to remove heat from the engine. In a closed cooling system, the coolant is circulated through a heat exchanger which removes heat from it prior to redirecting the coolant back to the engine cooling passages. In an open cooling system, water is obtained from a body of water and directed through the cooling passages. After the water removes heat from the engine, it is returned to the body of water. Open cooling systems can be subject to blockage by debris that is in the body of water in which a marine vessel is operated. The debris is taken into the cooling system, typically by a water pump, and flows, through the cooling channels of the engine""s cooling passages. The debris can block the cooling passages.
Conventional mechanical thermostats are commonly used to regulate the flow of coolant through cooling passages of an internal combustion engine. Because of their structure and theory of operation, conventional mechanical thermostats are typically designed to result in a preselected temperature of water flowing through the thermostat or in thermal communication with it. Regulation of the temperature of the cooling system to a desired temperature that is not identical to the temperature range of the conventional mechanical thermostat cannot be done with conventional thermostat system. In addition, opening or closing the conventional mechanical thermostat by a remote control means is also not typically possible.
It would be significantly beneficial if an engine cooling system could be provided that is controllable to different temperature ranges, as a function of operating conditions of the engine, and which can also be manipulated in such a way that debris can be removed from certain blocking positions within the cooling system.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
A temperature regulation system for an internal combustion engine, made in accordance with the preferred embodiment of the present invention, comprises a fluid passage disposed in thermal communication with a heat producing portion of the internal combustion engine, a valve connected in flow controlling relation with the fluid passage, a temperature sensor disposed in thermal communication with a preselected portion of the internal combustion engine, and a microprocessor connected in signal communication with the temperature sensor and with the valve.
The valve has a first state in which cooling water is permitted to flow through the fluid passage and a second state in which cooling water is prevented from flowing through the fluid passage. The microprocessor is configured to cause the valve to switch between the first and second states as a function of a signal received from the temperature sensor which is representative of a temperature at the preselected portion of the internal combustion engine. The valve is connected to the fluid passage at a location which is downstream from the engine and in a discharge passage of the fluid passage. The system can further comprise a pump connected in fluid communication between the fluid passage and a source of water, such as a body of water.
Although the present invention is described in terms of a valve having a first state and a second state which represent open and closed positions, respectively, it should be clearly understood that alternative valves can be used. These alternative valves can have many optional states between fully opened and fully closed. A ball valve, for example, can be moved to any one of a plurality of positions between fully opened and fully closed. Valves of either type can be used in conjunction with the present invention.
A method for controlling a cooling system of an internal combustion engine, in accordance with the preferred embodiment of the present invention, comprises the steps of providing a fluid passage disposed in thermal communication with a heat producing portion of the internal combustion engine, providing a valve connected in flow controlling relation with the fluid passage, providing a temperature sensor disposed in thermal communication with a preselected portion of the internal combustion engine, and providing a microprocessor connected in signal communication with the temperature sensor and with the valve.
The method can further comprise the steps of measuring a temperature of the preselected portion of the internal combustion engine, comparing the temperature of the preselected portion of the engine to a preselected desired temperature or temperature range, causing the valve to assume a first state when the temperature exceeds the desired temperature and causing the value to assume a second state when the temperature is less than the desired temperature. The first state is representative of a greater flow of fluid through the fluid passage than the second state.
The method of the present invention can further comprise measuring the temperature of the preselected portion of the internal combustion engine when the valve is expected to be in the second state and then causing the valve to assume the first state for a preselected period of time when the temperature is less then a predetermined expected temperature as a function of the valve being in the second state. This method further comprises the step of causing the valve to assume the second state subsequent to the step of causing the valve to assume the first state for a preselected period of time.